Stopcock control device



Patented June 1, 1943 UNITED STATES PATENT OFFICE STOPCOCK CONTROL DEVICE Application March 5, 1941, Serial No. 381,866

11 Claims.

Our invention relates to a control device for valves and more particularly to a control means for a burette stopcock.

I-n the use of the conventional burette for titrations the titrant is permitted to run from the burette through the stopcock into the solution being titrated at a rapid rate until the end point is approached. From this point to the end point the titrant is added one drop or a few drops at a time, requiring the laboratory technician to cautiously open the stopcock only sufiiciently to permit a very small flow to pass therethrough into the solution, whereupon the stopcock is closed and the solution being titrated is stirred and observed. 'Ihis operation must frequently be repeated with the utmost constant care on the part of the technician as often as a dozen or more times. Frequently, even with the most diligent attention and the steadiest hand, the technician permits more than the desired small increment of titrant to pass through the stopcock of the burette into the solution at the crucial stage of titration, vitiating the results and requiring a repetition oi the titration.

It is an object of our invention to provide a control device for a burette stopcock which restrains the rotation of the valve body at that position in the valve barrel required to deliver drops of the titrant from the burette at the desired rate.

It is sometimes desirable to permit the titrant to run from the burette to the solution being titrated in a stream instead of in drops and at a rate less than the flow when the stopcock is in its Iully opened position.

It is the corresponding object of our invention to provide a control device for a burette stopcock operative to restrain the rotation of the valve plug or body at a plurality of positions in the valve barrel, one position being that at which the titrant is delivered in drops at the desired rate and another position being that at which the titrant is delivered in a stream at a rate of flow greater than the rate of drop delivery and less than the rate of flow when the stopcock is fully opened.

It is another object of our invention to provide such a control device, which is adjustable to permit the easy and quick variation of the positions of the valve body at which its rotation is restrained. Such a device is of great utility when attached to a stopcock having a multiplicity of passages in the barrel and one or more passages in the valve body, making it possible to set the valve body with certainty at any position causing communication between any of the passages corresponding to the rate of iiow desired.

In the laboratory use of a burette it is sometimes desirable to turn the valve body of the stopcock to its fully open position and thereafter to turn the valve body to an intermediate position, permitting the discharge of the titrant in a stream at a rate of flow less than the maximum rate of flow or to a position permitting the delivery of the titrant in drops. It is an object of our invention to provide a control device for such a stopcock, permitting such an operation to be performed by virtue of its inclusion of a stop impeding, but not preventing, rotation of the valve body beyond a predetermined position, or by virtue of its including elements interengaging to restrain rotation of the valve body at a predetermined position, one of which elements is easily movable to non-engaging position to free the valve body for rotation beyond such predetermined position.

Still another object of our inventionis to provide a control device of the character describedwhich does Inot interfere with the manipulation of or contact the handle of the stopcock.

The valve body or valve plug of a burette stopcoclr is most frequently made irusto-conical in form and seated within a frusto-conical valve barrel in sealing relationship therewith. Care must be taken not to exert a, pressure upon the valve body or plug in a direction urging it out of the valve barrel or out of its seated position. It is an object of our invention to provide a control device for a stopcock which does not urge the valve plug or body out of the barrel, but on the contrary resiliently urges it into seated position and sealing engagement with the valve barrel at all stages of its rotation relative thereto.

Other objects of our invention include the proforming the foregoing objects and providing the described advantages are disclosed in the following specication, which may be better understood by reference to the accompanying drawing. l

In the drawing, which is for illustrative purposes only,

Fig. 1 is a side elevational view of one embodiy ment of our invention installed upon a burette stopcock;

Fig. 2 is a fragmentary sectional View taken as indicated by the line 2 2 of Fig. 1;

Fig. 3 is an end elevational view oi the apparatus illustrated in Fig. 1;

Fig. 4 is a perspective view of that embodiment illustrated in Figs. 1 to 3 removed from the burette stopcock;

Fig. 5 is a side elevational view, partially in section, of another embodiment of the control device of our invention;

Fig. 6 is an end elevational view of the apparatus illustra-ted in Fig. 5; and

Fig. 7 is a perspective view of the detachable engaging means shown in Figs. 5 and 6.

Referring to the embodiment illustrated in Figs. 1 to 4, inclusive, the numeral I I indicates a burette of conventional form, having integral therewith a valve barrel I2 with a frusto-conical cavity I3 therein, as indicated by the dotted lines of Fig. 1. Seated in the cavity I3 and in sealing relation with the walls thereof is a frusto-conical valve body or valve plug I4, provided with a handle I5 at that one of its ends of larger diameter. The end portion of the valve body I4 of lesser diameter, indicated by the numeral I5 of Fig. 1, projects outwardly from the valve barrel I2. The valve barrel I2 has inlet and outlet openings I1 and I8 therein, and the valve body I4 has a passage I9 therethrough, adapted to fully register with the inlet and outlet openings I1 and I8 when the Valve body I4 is in its fully open position and to be fully out of registry with one or both of the openings I'I and I8 when the valve body I 4 is rotated to fully closed position.

While the drawing illustrates a single passage stopcock on a burette, the invention is capable of use with a stopcock in any now-line, and to a stopcock having a plurality of outlet openings in the barrel and one or more passages in the valve body.

This embodiment of the control device of our invention includes a first means, which may be described as an engaging or detachable means, indicated by the numeral 23 and a second means, which may be described as engaging means, or detachable means, or stop-supporting means, indicated by the numeral 2|. rIhe first engaging means 20 includes two blocks 22 and 23, which may be formed of metal or of a plastic or the like, which blocks are provided on their inner faces with substantially semi-cylindrical cavities 24 adjacent each other. Lining the cavities 24 is a pad means 25 in the form of a sheet or layer of cork, rubber, or other suitable cushioning or resilient material.

Each of the blocks 22 and 23 is also provided with a transversely or horizontally extending cavity 26, shaped to conform to the valve barrel I2. The pad means 25 may extend throughout the length of the cavities 24 and across the cavity 25, or the pad means 25 may extend throughout the length of the cavity 26 and across the cavities 24, or, if desired, the pad means 25 may cover such portions of the walls defining the cavities 24 and 26 as required to provide the desired cushioning or resilient effect when clamped between the blocks 22 and 23 and the burette I I and valve barrel I4.

The blocks 22 and 23 are retained in engagement with the valve barrel I4 by screws 21, illustrated in the drawings as four in number, passing through the block 22 and threaded into the block 23. Suitably secured to the block 22, as by two of the screws 21, is an arm 28, which extends horizontally beyond and vertically above the block 22. Threaded through the arm 28, adjacent its upper end, is an engager element or first interengaging means in the form of an adjusting screw 29, having thereon a lock nut 30, adapted by its bearing against the arm 28 to hold the adjusting screw 29 in the desired position.

The second engaging means 2| includes a collar 3|, having therein a central opening 32 of a form and diameter to accommodate therein the projecting end portion I6 of the valve body I4. The collar 3| is provided with a radial opening 33, and a lock screw 34 bearing against a shoulder 35 in the periphery of the collar on one side of the opening extends across such opening and is threaded into the collar on the opposite side thereof. By tightening the lock screw 34, the radial opening 33 is reduced, and the collar 3| is clamped to the projecting end portion I6 of the valve body I4, the lock screw 34 thus acting as a means for mounting or adjustably clamping the second engaging means 2| to the valve body I4. A coil spring 38 is positioned around the project-1 ing end portion I6 of the valve body I4 with one end bearing against the collar 3| and the other end bearing against the blocks 22 and 23. If desired, a pad means similar to the pad means 25 previously described may be positioned between the wall of the central opening 32 in the collar 3| and the projecting end portion I6 of the valve body I4.

Mounted upon the lock screw 34 within the radial opening 33, so as to be capable of swinging movement relative thereto, is a second interengaging means or stop element 35. As is best illustrated in Fig. 4, the stop element 36 has a projecting portion 31 at its outer end extending towards the blocks 22 and 23 in position to contact the adjusting screw 29 when the valve body I4 is rotated. Illustrated in Figs. 1, 3, and 4 is a second stop element or member 35a, mounted upon a lock screw 34a so as to be swingable in a radial opening 33a in the collar 3|, in all'respects like the elements 33 to 36 previously described. T.f desired, a light coil spring 38 may be interposed between the ends of the blocks 22 and 23 or the adjacent end of the valve barrel I2 and the inner side of the collar 3|, as illustrated in Fig. l.

With this embodiment oi our invention it will be apparent that the blocks 22 and 23 may be readily clamped upon the valve barrel I2 by threading the screws 27 into the block 23, and the second engaging means 2| may also be readily clamped upon the projecting portion I6 of the valve body I4 by tightening one of the screws 34 or 34a. The second engaging means 2| is thus clamped in such a position upon the valve body I4, and the adjusting screw 29 is so adjusted and locked in position by the lock nut 3U that, when the projecting portion 3'!a of the stop element 36a contacts the end or the adjusting screw 29, the passage I 3 in the valve body I4 communicates with the inlet and outlet openings I'I and I8 in` the valve barrel I2, so that liquid is delivered from the burette II in drops at the desired rate during titration. Both the stops 36 and 36a may be moved to positions avoiding contact with the adjusting screw 23, so that the valve plug I4 may be rotated to fully open position, causing the delivery of titrant from the burette I I at the maXimum rate of flow. If desired, either at the beginning or at an intermediate stage of the titrating process the valve body I4, with the stop element 33 in operative position, may be rotated from its nearly closed position to a position in which the projecting portion 31 thereof engages the adjusting screw 29, restraining the rotation of the valve body I4 at a position of communication of its passage I9 with the inlet and outlet openings |1 and I8, permitting the discharge from the burette I| of liquid at an intermediate rate of flow.

It will be seen that the installation or removal of the control device of our invention does not require the removal of the valve body I4 from the valve barrel I2 or its movement relative thereto into unseated position. It will further be seen that our control device does not interfere with the manipulation of or contact the handle I5. At all positions of the valve body |4 the coil spring 38 acts to resiliently urge the valve body |4 into the cavity I3 of the valve barrel I2 and thus into seated position by virtue of its pressure upon the second engaging means 2| secured to the projecting end portion I6 of the valve body I4.

Referring to the embodiment of our invention illustrated in Figs. 5 to 7, inclusive, the numeral IIa indicates a burette having a valve barrel I2a with a frusto-conical cavity I3a in which the valve body |4a is seated. The valve body I48L has on its end of larger diameter a handle |53, and its end portion of lesser diameter IIia projects from the valve barrel. The elements indicated by the elements |22L to I6a correspond to the elements I2 to I6 previously described. The valve barrel |2a has inlet and outlet openings, and the valve body |4=1L has a passage therethrough like the openings |1 and I8 and passage I9,

respectively, in the embodiment earlier described.

In this embodiment of our invention the rst engaging means or detachable means is in the form of a wire element or clamping member, indicated by the numeral 39. The wire element 39 includes central looped portions 4D formed to encircle and be supported upon the valve barrel |2a and end portions 4| and 42 resiliently engaging the burette I |a and clamping the wire element 39 in position. The end portion 42 is provided at one end with an eye 43, swingably mounted in an eye 44 at one end of one of the central portions 40. The other end of the end portion 42 is retained in position resiliently engaging the burette ||L by an inwardly curved portion 45 at one end of the other central portion 40. The wire element 39 is formed of resilient material, so that the end portion 42 and that one of the central portions 40 engaging its free end may be deformed to permit the end portion 42 to be swung free of the curved portion 45 and released from the burette IIa. The central portions 40 of the wire element 39 may then be moved apart axially of the valve barrel |28, permitting these central portions 40 to be freed of the valve barrel |2.

At the juncture of the end portion 4| and the central portion 40 opposite the handle I5a is provided an engaging portion or rst interengaging means 46 formed by bending the end portion 4| upon itself in a U-shape, so that the projecting end of the first interengaging means is rounded.

The numeral 41 indicates a second engaging or detachable means, or stop-supporting means, or stop member in the form of a disc having a hub 48 and a central opening 49 formed to accommodate the projecting portion Isa of the valve plug |4a. Means for adjustably clamping the disc 41 to the valve plug I4a is provided in the form of a set screw 50 threaded through the hub 48 into engagement with the projecting portions |69 of the valve plug |49. The disc 41 is formed of a diameter such that its inner surface will engage the first interengaging means 46 of the wire element 39 at all positions of the valve plug I4ab during its rotation. One or more second interengaging means, or stop elements, or stops are provided upon the disc 41 at locations in which they will be contacted by the first interengaging means 46 at desired positions of the valve body |42. These stops may be in the form of indentations, projections, or slots. In the drawing we have illustrated three such stops, 5|, 52, and 53, in the form of slots extending radially inwardly from the periphery of the disc 41. The slots 5|, 52, and 53 are formed of a width less than the width of the rst interengaging means 46, so that only the rounded end thereof may extend into the slots. Thus, when the iirst interengaging means 46 contacts one of the slots 5|, 52, or 53 the rotation of the disc 41 and valve body |4a is resisted, but not prevented, and the disc 41 and valve body I 4a may be further rotated by an increase in rotative force upon the handle |5a.

If desired, a pad means, suoli as the pad means 25 of the embodiment previously described, may be positioned between the walls of the central opening 49 in the disc 41 and the projecting portion |6a of the valve body |45. Likewise, the contact between the wire element 39 and the valve barrel I2EL and burette I la, or either of them, may be cushioned by surrounding the wire element or desired portions thereof with a layer of rubber, silk wrapping, or other resilient, or cushioning material.

The stops 5|, 52, and 53 may be so located in the disc 41 and the disc 41 so positioned upon the valve body I4a that, when the valve body IIIEL is rotated in a clockwise direction, as viewed in Fig. 6, the rst interengaging means moves into contact first with stop 53, then with stop 52, and finally with stop 5| to permit delivery of titrant from the burette in a stream at a rate of flow less than that permitted when the stopcock is in its fully opened position. At the desired point in the titration process the valve body I4a may be rotated until the rst interengaging means 46 contacts the stop 52, restraining the rotation of the valve body I4a in position where the titrant is delivered from the burette in a stream at a lesser rate of ow. Subsequently in the process the valve body may be further rotated until the rst interengaging means 46 contacts the stop element 53, at which time the titrant is delivered in drops at the desired rate.

The wire element 39, being formed of resilient material, the first interengaging means 46 is constantly urged into resilient contact with the inner surface of the disc 41, thus exerting upon the disc 41 and the valve plug |49b a force urging the valve body I4a into seated engagement with the valve barrel |211. The resiliency of the wire element 39 permits movement of the first interengaging means 46 towards the handle I5ab when additional rotative force is applied to the handle I5a to move the valve plug out of that position in which the rst interengaging means 46 contacts one of the stops 5|, 52, or 53. Likewise, this resiliency permits the operator to manually move the end portion 4| towards the handle I5a if he wishes to free the disc 41 from contact with the first interengaging means 46 to facilitate the more rapid rotation of the valve body.

In both embodiments of our invention, when the end point is approached, the handle of the valve body is rotated from the fully closed po sition of the valve body until the first interengaging means 2i) or 4S contacts the nearest stop or stop elements 36a or 53, respectively. As soon as thedesired number of drops of the titrant are delivered from the burette, the valve body is moved back to its fully closed position until the effect of the drops delivered may be observed. Thus the technician is enabled to very quickly and with certainty move the valve body to that position at which only a single drop at a time is delivered, thereby greatly reducing the time required for the titration and eliminating the possibility of a vitiating of the titration by the involuntaiy delivery of an excess of the titrant.

From the foregoing description of this embodiment of our invention it will be seen that there is provided a control device restraining the rotation of the stopcock at a plurality of positions in the valve barrel, one position being that at which the titrant is delivered in drops at the desired rate and another position being that at which the titrant is delivered in a stream at a rate of flow less than the rate of ow when the stopcock is in its fully open position. It will be seen also that by virtue of the resilience of the wire element 39, this embodiment provides a control device in which the movement of the valve body of the stopcock is impeded, but not prevented, at a predetermined position in the valve barrel and a device in which such predetermined positions may be quickly and easily changed by loosening the set screw 59, rotating the disc 47 relative to the valve body 14e, and

again clamping the set screw 5l] to the valve body. The resilience of the wire element 39 has the further effect of urging the valve body Wl into seated relationship with the valve barrel i 2a at all stages of the rotation of the valve body [4a by virtue of the pressure of the rst interengaging means 46 upon the disc 47.

In accordance with the objects first herein stated, it will be obvious that; both embodiments of our invention may be quickly and easily installed upon the burette without removing or unseating the valve body and that both forms of our invention may be inexpensively manufactured.

While those embodiments of our invention herein particularly illustrated and described are fully capable or" performing the objects and accomplishing the advantages primarily stated, and while `our invention has been illustrated and described as applied to a burette stopcock, it is to be understood that there are Various other embodiments of our invention also capable of performing these objects and accomplishing these advantages and that our invention is capable of application to valves other than burette stopcocks and to stopcocls having a plurality of passages, and is, therefore, not restricted to the specinc embodiments or use hereinbefore described.

We claim as our invention:

l. A device for controlling the rate of Ilow of duid through a burette stopcock including a valve barrel having a frusto-conical cavity with inlet and outlet openings communicating therewith, and a frustomconical valve body rotatable in said cavity in sealing relationship with its walls and having ends projecting from said cavity, said valve body having passage means so disposed that said valve body may be rotated to provide maXimum and reduced rates of iiow therethrough and to entirely shut oir the flow therethrough, which device includes in combination: a clamping means acadien dctachably secured to said burette adjacent said valve barrel; a iirst engaging means carried by said clamping means at a position near said valve barrel; a second engaging means detachably clamped to that protruding end of said valveA body which is of smaller diameter, said first and second engaging means contacting at a predetermined position of said Valve body relative to said valve barrel; and means pressing against said second means to eXert a force thereon in a direction tending to prevent unseating of said valve body relative to said cavity.

2. In a control device for a stopcock, having a valve barrel with inlet and outlet openings and a valve body rotatable in said barrel to control the flow of fluid therethrough, said valve having a handle at one end thereof, the combination of detachable means adapted to Abe secured to said Valve barrel and providing an engager element adjustably mounted on said means and projectin therefrom out of the path of travel of said handle; stop-supporting means adjustably secured to said valve body at that end thereof opposite said handle; a plurality of stop elements mounted on said stop-supporting means, each of said stop elements being movable independently of the other stop elements between a position avoiding contact with said engager element to a position contacting said engager element at a predetermined position of said valve body relative to said valve barrel; and resilient means between said stop-supporting means and said valve barrel urging said valve body into sealing engagement with said barrel.

8. In a control device for a valve on a burette including a barrel with inlet and outlet openings and a plug therein, said plug having a handle at one end and having a passage therein and being rotatable between fully open position with said passage in complete registry with said openings and fully closed position with said passage completely out of registry with said openings, the combination of: a clamping member around said barrel and resiliently engaging said burette, said member having an engaging portion projecting therefrom and resilicntly urged by said member in a direction away from said burette; and a disc mounted on said plug adjacent that end opposite said handle, said disc `being of such diameter as to be resiliently engaged by said engaging portion during rotation of said plug, and said disc being providedwith a stop thereon engageable with said engaging portion at a predetermined position of said plug relative to said barrel.

4. In a device adapted to be connected to a stopcoclr of a burette to restrain the valve body thereof in a predetermined position, the combination of: a wire element disposed around said stopcock and providing an engaging portion, a central portion looped around said stopcock and two end portions cooperating to grip said burette from opposite sides; and a stop member detachably connected to said valve body and providing means thereon contacting said engaging portion of said wire element at said predetermind posi-l tion of said valve body.

5. In a control device for a stopcock on a burette including a barrel with inlet and outlet openings therein and a frusto-conical valve body seated therein and having a passage therein in registry with said openings in the fully open position of said valve body and out of registry with said openings in the fully closed position of said valve body, the combination of: a stop member releasably and adjustably secured tothe reduced end of said valve body; a plurality of stops carried by said member; a clamping member having portions supported upon said barrel and portions resiliently engaging said burette, one of said burette-engaging portions being swingable relative to said clamping member out of contact with said burette; and an engaging portion carried by said clamping member and resiliently engaging said stop member at all positions of said valve body and urging said valve body into seated position in said barrel and contacting said stops at predetermined positions of said valve body.

6. In a device adapted to `be connected to a stopcock of a burette, said stopcock having a valve barrel providing protruding ends and having inlet and outlet openings and a ported valve body in the barrel, said valve body having a handle at one end, the combination of: detachable means adapted to be secured to said valve barrel, said means providing two spaced portions shaped to conform generally to the periphery of said protruding ends, said two spaced portions extending at least partially around said protruding ends in encompassing relation; a yieldable engaging portion carried by said detachable means at a position on the side opposite said handle; a stop-supporting member releasably secured to the valve body at the end opposite said handle; and a plurality of stop means provided by said stop-supporting member for engagement with said yieldable engaging portion thereby to cause perceptible but yielding resistance to rotation of the valve body at a predetermined position of the valve body to facilitate adjustment of the valve body to said position.

7. In a control device for a burette providing a valve arrangement including a valve barrel having a frusto-conical cavity and a frusto-conical valve body rotatably mounted in said cavity, the smaller end of said valve body projecting from the barrel, the combination of: a clamping means detachably secured to said burette adjacent said valve barrel and providing surfaces generally conforming in shape to the exterior of a portion of said burette; a first means mounted on said projecting end of the valve body; and a second means mounted on said clamping means, one of said means being in pressural cooperation with the other to urge said valve body toward the smaller end of said cavity, one of said means cooperating with the other to resist rotation of said valve body at a predetermined position of the valve body to facilitate adjustment ofthe valve body to said predetermined position.

8. As a new article of manufacture, a nowcontrol device for use on a valve having a valve barrel with a frusto-conical seat and a frustoconical valve body mounted therein with the smaller end of the valve body projecting from the valve barrel, said now-control device comprising: a iirst means for mounting on said projecting end of the valve body; and a second means for mounting on said barrel, one of said means being adapted for pressural cooperation with the other to urge said valve body into said seat, one of said means being adjustable between a noncontrolling position and a controlling position at which controlling position it is eiective to cooperate with the other means to resist rotation of the valve body at a selected rotary position of the valve body thereby to facilitate 4adjustment of the valve body to said position.

9. An attachment for a burette comprising a fluid-containing tube and a transverse valve barrel providing exposed ends protruding on opposite sides of said tube, there being a tapered valve body rotatable in a tapered bore of said barrel and providing a passage registerable With passages of said barrel to pass iluid from said tube, said valve bodjr having a handle at one end and positioned beyond one of said exposed ends of said barrel, said attachment including in combination: a clamping means detachably connected to said burette and providing two spaced portions shaped to conform generally to the periphery of said exposed ends of said valve barrel, said two spaced portions at least partially encompassing said exposed end; a iirst inter-engaging means .carried by said clamping means and presenting an engaging surface disposed adjacent one end of said barrel; a member releasably secured to said valve body adjacent said one end of said barrel; a second inter-engaging means provided =by said member for inter-engagement with said iirst interengaging means at a predetermined position of said valve body with respect to said valve barrel; and means for movably mounting one of said inter-engaging means for retraction from engagement with the other inter-engaging means during the time that said member is secured to said valve body.

10. An attachment for a burette comprising a fluid-containing tube and a transverse valve barrel providing exposed ends protruding on opposite sides of said tube, there being a tapered valve body rotatable in a tapered bore of said barrel and providing a passage registerable with passages of said barrel to pass fluid from said tube, said valve body having a handle at one end and positioned beyond one of said exposed ends of said barrel, said attachment including in combination: a clamping means detachably connected to said burette and providing two spaced portions shaped to conform generally to the periphery of said exposed ends of said valve barrel, said two spaced portions at least partially encompassing said exposed ends; a first inter-engaging means carried by said clamping means and presenting an engaging surface disposed adjacent one end of said barrel; a member releasably secured to said valve body adjacent said one end of said barrel; a second inter-engaging means provided by said member for inter-engagement with sa'id first nter-engaging means at a predetermined position of said valve body with respect to said valve barrel; and resilient means for urging one of said inter-engaging means into yieldable engagement with the other of said inter-engaging means at said predetermined position of said valve body with respect to said valve barrel to cause perceptible but yielding resistance to rotation of said Valve body at said predetermined position to facilitate adjustment of the valve body to said position, said resilient means being mounted to exert a force against said member in a direction tending to draw said tapered valve body into said tapered bore of said valve barrel.

11. A combination as defined in claim 9, in which one of said inter-engaging means comprises a stop element engageable with the other of said inter-engaging means at said predetermined position, and in 4which said means for movably mounting one of said inter-engaging means comprises pivot means for pivoting said stop element to a position at which it will not engage said other inter-engaging means at said predetermined position.

RICHARD W. STENZEL. JAMES G. SUTHARD. 

